1. Field of the Invention
The instant disclosure relates to a dimming method; in particular, a dimming method operated in a composite way.
2. Description of Related Art
In recent years, many electronic products are equipped with display screens; these electronic products are such as mobile phones, personal digital assistants machines (Personal Digital Assistant, PDA), digital music players and car dashboards. Although types and sizes of the screens are usually determined according to their applications, design engineers still have to design lighting circuits. Most displays, including thin film transistor liquid crystal displays, are in need of backlighting so that users are able to see graphics and texts on the screens. A light-emitting diode backlight module is often used in the electronic products. To achieve a uniform backlighting, a color liquid crystal display screen needs three to four or more light emitting diodes, and a backlight of the dashboard may require six or even more light emitting diodes. Due to an increase of demand for the light-emitting diodes, a strong impetus of growth of the market for light-emitting diodes is developed.
However, there is an acoustic noise easily generated by back-light modules with organic light-emitting diodes as a light resource. With more opportunities for portable electronic devices, such as the mobile phones, to get close to ears of the users; the users are under more chances of disturbances caused by the acoustic noise. Based on the related art, problems caused by the acoustic noise require an individual adjustment or modification, consuming a great amount of labor, time, and money.